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Unified training-part-b

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Unified training-part-b

  1. 1. Unified Soil Classification System Training Part B - USCS using Laboratory Data
  2. 2. Comparison of Particle Size Definitions # 200 USDA cobbles sand clay gravel 3” 2  .05 mm # 4 silt USCS cobbles sand fines gravel .074 mm # 4 3”
  3. 3. ASTM Standards <ul><li>Lab Data Classification is by ASTM D2487 </li></ul><ul><li>Classification of Peat Samples, see ASTM D 4427 </li></ul><ul><li>Field Classification is by D2488 </li></ul>
  4. 4. Comparison of Particle Size Definitions
  5. 5. Activity 2 - Particle Size Comparisons
  6. 6. USCS Flow Chart - Activity 3
  7. 7. Flow Chart Overview <ul><li>Two Broad Categories </li></ul><ul><ul><li>Fine-Grained - 50% or more finer than the # 200 sieve </li></ul></ul><ul><ul><li>Coarse-Grained - Less than 50% finer than the # 200 sieve </li></ul></ul>
  8. 8. USCS Overview
  9. 9. Flow Chart Overview <ul><li>Fine-Grained Soils </li></ul><ul><ul><li>Organic ( LL ratio < 0.75 ) </li></ul></ul><ul><ul><li>Inorganic (no odor and LL ratio not < 0.75) </li></ul></ul><ul><ul><li>Classify by LL, PI </li></ul></ul><ul><ul><li>Modifiers are H or L for LL value, C or M for plasticity and O for organic </li></ul></ul>
  10. 10. USCS Overview
  11. 11. Activity 4 - Organic Soil Solve 4 samples
  12. 12. Abbreviations Fine-Grained <ul><li>H - High LL ( > 50 ) </li></ul><ul><li>L - Low LL ( < 50 ) </li></ul><ul><li>C - Plastic Fines </li></ul><ul><li>M - Nonplastic or slightly plastic fines </li></ul><ul><li>O - Organic </li></ul><ul><li>Pt - Peat </li></ul>
  13. 13. Activity 5 - Plasticity Chart
  14. 14. Activity 5 - Plasticity Chart Solve 4 samples
  15. 15. Activity 7 - Classify Fine-Grained Samples Assume 6 samples are not organic and classify by USCS
  16. 16. Flow Chart Overview <ul><li>Coarse-Grained Soils - 3 Groups </li></ul><ul><ul><li>Clean - Less than 5 % Fines </li></ul></ul><ul><ul><li>Dirty - More than 12 % Fines </li></ul></ul><ul><ul><li>Dual - From 5% to 12% Fines, inclusive </li></ul></ul>
  17. 17. Coarse-grained Soils
  18. 18. Abbreviations Sands and Gravels <ul><li>G - Gravel </li></ul><ul><li>S - Sand </li></ul><ul><li>P - Poorly Graded </li></ul><ul><li>W - Well Graded </li></ul>
  19. 19. Sieve Analyses % fines = % finer than # 200 sieve % sand = % finer # 4 minus % finer # 200 % gravel = % finer 3”minus % finer # 4
  20. 20. Percent Particle Categories <ul><li>To compute % Gravel subtract % finer than # 4 from % finer than 3” </li></ul><ul><li>To compute % Sand subtract % finer than # 200 from % finer than # 4 </li></ul><ul><li>Percent Fines is % finer than # 200 </li></ul>
  21. 21. Activity 8 For 7 samples, fill out Activity
  22. 22. Additional Definitions <ul><li>To Classify Clean Coarse-Grained Soils, you must first plot grain-size curve and determine three parameters </li></ul><ul><li>D 10 , D 30 , D 60 </li></ul>
  23. 23. Determining D 10 , D 30 , and D 60 D 10 , millimeters 10 % finer D 30 , millimeters 30 D 60 , millimeters 60
  24. 24. Computing CU and CC Coefficient of Uniformity Coefficient of Curvature High Values Indicate Well-Graded Soil Values Between 1-3 Indicate Well-Graded Soil
  25. 25. Activity 9 Plot Curve from Data, compute CU Value
  26. 26. Activity 10 Plot Curve from Data, compute CC Value
  27. 27. C haracterizing Clean Sands and Gravels <ul><li>Clean Well Graded Sands and Gravels have less than 5 % fines and a wide range of particle sizes that are equally distributed </li></ul>Particle Size % Finer Well graded
  28. 28. Poorly Graded Sands and Gravels Poorly graded % Finer Particle Size Either Mostly One-Size Particle Gap graded Particle Size % Finer Or Gap- Graded
  29. 29. Clean, Well/Poorly Graded Definitions <ul><li>Sands </li></ul><ul><ul><li>less than 5 % fines </li></ul></ul><ul><ul><li>CU > 6 </li></ul></ul><ul><ul><li>CC = 1-3 </li></ul></ul><ul><li>Gravels </li></ul><ul><ul><li>less than 5 % fines </li></ul></ul><ul><ul><li>CU > 4 </li></ul></ul><ul><ul><li>CC = 1-3 </li></ul></ul>
  30. 30. Activity 11 - Problems <ul><li>1. Verify % Fines - Coarse-Grained/Clean </li></ul><ul><li>2. Compute % Gravel and % Sand </li></ul><ul><li>3. Note which predominates </li></ul><ul><li>4. Using provided CU and CC, Determine whether poorly or well graded </li></ul><ul><li>5. Determine Correct USCS classification </li></ul>
  31. 31. Activity 12 Review Example Soil
  32. 32. Activity 13 Use Flow Chart, Classify Soil
  33. 33. Activity 14 Summary of Classifications of Coarse-Grained Soils <ul><li>Clean Sands and Gravels (< 5% fines) </li></ul><ul><ul><li>Clean Poorly Graded Gravels GP </li></ul></ul><ul><ul><li>Clean Well Graded Gravels GW </li></ul></ul><ul><ul><li>Clean Poorly Graded Sands SP </li></ul></ul><ul><ul><li>Clean Well Graded Sands SW </li></ul></ul>
  34. 34. Dirty Coarse-Grained Soils <ul><li>If a sample has less than 50 % Fines </li></ul><ul><li>And it has more than 12 % Fines, it is a Dirty Coarse-Grained Soil </li></ul><ul><li>To Classify, follow the flow chart and the following steps </li></ul>
  35. 35. Dirty Coarse-Grained Soil <ul><li>Determine whether there is a greater % of Sand or Gravel </li></ul><ul><ul><li>% G = % finer 3” minus # 4 </li></ul></ul><ul><ul><li>% S = % finer # 4 minus # 200 </li></ul></ul><ul><li>Determine where minus # 40 fines plot on plasticity chart </li></ul>
  36. 36. Dirty Sands and Gravels <ul><li>SC - Fines Plot Above A-Line </li></ul><ul><li>SM - Fines Plot Below A-Line </li></ul><ul><li>SC-SM - Fines Plot in Hatched Zone </li></ul><ul><li>GC - Fines Plot Above A-Line </li></ul><ul><li>GM - Fines Plot Below A-Line </li></ul><ul><li>GC-GM - Fines Plot in Hatched Zone </li></ul>Sands Gravels
  37. 37. Activity 16 - Problems
  38. 38. Activity 17 - Example of Classifying Dual-Classification Coarse-Grained Soil
  39. 39. Activity 18 - Problem
  40. 40. Activity 20 - Review Questions
  41. 41. Activity 21 - Comprehensive Problems

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